SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7ade31fea08e560afc78d4b536ed00b092351ded294e8ba385453a3d828c12e' 
  AND token = 'zQ6YUZZqTmXukQBSqnnbtUPHc3Gvi153qqlsaQ6XGE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}